The decade between 1987 and 1997, spanning the Diabetes Control and Complications Trial (DCCT) and other clinical trials, saw confirmation of the importance of intensive therapy to control glycemic levels in Type 1 diabetes. Accompanying this advance in diabetes treatment, molecular studies emerged and provided clues to possible pathways for long term vascular complications perhaps most notably in the area of advanced glycation end products. The investigators' point out that their geographically based cohort presents an excellent opportunity to examine how these recent advances in clinical diabetes and basic science apply to prevention of complications in the community. Detailed information from this cohort followed from diabetes diagnosis during 1987-1992 includes a valuable longitudinal plasma bank. The cohort provides a unique baseline to compare diabetes management, glycemic control and outcomes in the post-DCCT era. As the investigators enrolled incident cases, they have information from diagnosis on children and adolescents. They propose to expand their existing data base, to use their existing resources including the plasma bank, and to incorporate promising new pathogenic testing by: (a) recruiting over 5 years a new post-DCCT cohort, (b) completing a 9 year follow-up for microvascular outcomes on the existing cohort, and performing antibody studies for methylglyoxal modified protein (an advanced glycation end product, or AGE) and sex hormone testing on our stored plasma. These proposed activities will allow the investigators to pursue the following specific aims: (1) compare trends in diabetes management and outcomes for individuals diagnosed before and after the announcements and dissemination of the DCCT results; (2) firmly establish retinopathy incidence and change in urinary albumin excretion rates through the first 9 years of Type 1 diabetes and their relationship to early risk factors; and (3) validate the role of a new plasma marker for intracellular AGE in glycemic control, retinopathy and change in urinary albumin excretion rates.